I hope I can explain myself here:
I agree that the main limiting factor is the gussets, because they in turn are influenced by the angular difference in operating plane of the adjacent run of panels.
A bellows "segment" has two transverse planes: one of fixed outside diameter, the outside fold. One of variable diameter, (of a fixed range, this is important) the inside fold.
The inside fold and outside folds are connected by the trapeziodal cards of fixed length.
There is no way (other than pulling the bellows apart and destryoing it) the inside plane can geometrically extend/expand beyond its range.
If if build a bellows endoskelton without gussets, remove it from the jig, it will extend to its maximum length and stop, dead, absolutely at its geometric limit.
The gussets do not serve to limit the movement and extension of the bellows at all.....unless they are installed short of the functional range of motion, in which case they do...and limit the extension of the bellows as a result.
Note that I am completely disregarding the flexibility of the cards themselves, which can provide a bit of vulgar and self-destructive flexibility on their own.
Gussets may be used as a "safety device" to limit the extension of the bellows and indeed this may be a good idea......because:
If the two planes of the bellows segment are not completely parallel or the cards are not glued properly in line, the plane itself will fail and the bellows will collapse or "blow out"
Poorly glued bellows cards can be recognized by a tearing sound at extreme extension, indicating delaminating of the cards.
I base the above on the strength of my experience building many bad bellows.
Edited by Bob Tedrow, 04 October 2003 - 12:26 PM.